That’s a pretty ridiculous point to make, unless:

a) You’re on such a low bandwidth connection that a few hundred bytes of transfer causes noticeable delays (in which case certainly don’t use Ext JS!)
b) You’re paying for your bandwidth by the byte (again, don’t use Ext JS)

Are you seriously suggesting that <> will have any noticeable impact on page load speed? That string of text can be represented using 72 bytes, which will easily fit in a packet along with a lot more page data. As a percentage of the size of the Ext JS library - which is of course required to even run the example - this comes to about 0.013%, depending on whether you load the full library or just cherry pick features to save bandwidth.

In any case this was a post about Rails checkboxes, and this is precisely how Rails expects checkbox data to arrive.

Nice post. Buried deep in my todo list is to write a ux to allow this to be added in one component. e.g.:

{
xtype: ‘rails_checkbox’,
fieldLabel: ‘Field Name’,
name: ‘model_name[field_name]‘
}

Which would be equivalent to:

{
xtype: ‘checkbox’,
fieldLabel: ‘Field Name’,
name: ‘model_name[field_name]‘,
inputValue: ‘1′
},
{
xtype: ‘hidden’,
name: ‘model_name[field_name]‘,
value: ‘0′
}